It give by default 10 results. I can add an additional filter top=1. Is this right ?
https://graph.microsoft.com/v1.0/me/mailFolders/Inbox/messages?$filter=isRead+ne+true&top=1
using Top will limit the results return no filter them if you want to make sure you always get the last message in the inbox you should also use orderby
Responses so far received are in JSON. How to get responses in MIME ? $value seems not supported for collections(messages)
Appreciate your assistance!
You can't return mime using the messages collection it must be done per message using the id of the message and the $value endpoint if you want to request multiple messages in one request then you can batch them https://learn.microsoft.com/en-us/graph/json-batching (you can do 4 concurrent request of 20 dependson)